A π-hole bond functionalized magnetic nanosorbent for the solid phase extraction of 15 polycyclic aromatic hydrocarbons from environmental water samples.

A new type of sorbent functionalized with π-hole bond, perfluoronaphthyl bonded magnetic nanosorbent (FeO@SiO-CF), was designed and synthesized. The morphology, structure and magnetic properties of the sorbent were characterized. The results of a comparative experiment with naphthyl bonded magnetic nanosorbent (FeO@SiO-CH) revealed that the π-hole bonds between perfluoronaphthyl and PAHs improved adsorbilities for PAHs in water compared to the traditional π-π interactions between naphthyl and PAHs. A new MSPE-HPLC method for the simultaneous detection of 15 PAHs in environmental water was established based on FeO@SiO-CF sorbent. This method requires less sorbent, offers high sensitivity, and allows for easy operation without solvent replacement. The results revealed that the method exhibited good linearity in the range of 0.05-12 ng·mL, and the recoveries of the PAHs in real samples ranged from 70.1 % to 108 % at the spiked concentration of 0.5 ng·mL, except for volatile naphthalene (41.8 %). The LODs were 0.2-13.4 ng·L. The results demonstrate the effectiveness of π-hole bond in extraction of PAHs, surpassing traditional π-π interaction even in water. The application of π-hole bond in sorbents offers a new interaction mode or retention mechanism in extraction processes, undoubtedly providing a fresh perspective for the design of selective sorbents.